The program project is aimed at understanding how diets high in fat lead to increased levels of[unreadable] defended body weight. Our overall strategy is to explore a model of dietary obesity at many levels and[unreadable] from multiple perspectives. The Animal & Physiology Core consolidates and centralizes the production of[unreadable] obese rats and their various control groups for each of the specific projects. Specifically, this core[unreadable] generates EVERY animal that is used in each of the specific projects and thereby assures that each[unreadable] experiment enjoys animals that have been treated in an identical manner, thus allowing comparisons[unreadable] across time, cohorts and projects. There are four primary goals of this core. 1) To generate requisite[unreadable] animals for the individual projects in any of the various dietary groups described in detail in the[unreadable] introductory section to the proposal. These groups include rats on a low-fat, semi-purified butter oil-based[unreadable] diet (LF), rats on a matched high-fat, semi-purified diet (HF), rats receiving the HF diet but with calories[unreadable] matched (pair-fed) to intake of the LF rats (PHF), rats receiving the LF diet and food-restricted by the[unreadable] same amount as the PHF: pair fed rats (PLF), and rats with pelleted chow (CHOW). The Core also[unreadable] generates control rats on HF and LF diets based on olive oil as opposed to butter oil. 2) To develop[unreadable] novel or modified rat surgical techniques as required by each of the individual projects. 3) To carry out[unreadable] experiments on behavioral aspects associated with the palatability and meal pattern analysis as well[unreadable] energy expenditure measurements to determine how the different fatty acids influence consumption and[unreadable] behaviors associated with body weight regulation. 4) To carry out carcass analysis for body lipid content[unreadable] on subjects from each of the individual projects. This includes non-invasive (i.e., NMR readings) and[unreadable] terminal assessments for the entire carcass or specific anatomical subareas (e.g., subcutaneous fat).[unreadable] Lastly, The Animal & Physiology Core will carry out certain pilot or other experiments necessary for[unreadable] creating data that are relevant and critical to the other projects. The Animal/Physiology Core personnel[unreadable] are already facile with all of the techniques required to date that are used to characterize the model;[unreadable] consequently the personnel are already well-trained and the protocols are all in place to efficiently[unreadable] accomplish the goals of this essential core.[unreadable]